When authors use http://schema.org/Action, they have two ways to specify the platform where the Action should be executed: http://schema.org/actionApplication or http://schema.org/target with the special prefix "android-app" or "ios-app" as appropriate. (See the examples in http://schema.org/EntryPoint.)

These mechanisms are insufficient as:

• They don't support mobile web apps very well. The author should not have to specify the specific browser app.
• There is no way to distinguish mobile web URLs from URLs intended for a desktop experience.
• Authors often want the abstract notion of a particular OS, not a specific version (e.g. iOS, not iOS 9).
• With Universal Links in iOS 9, the Action will have a single URL regardless of platform.

To make it easier for developers to specify which platforms support their Action URLs, I propose the following:

• A new property on http://schema.org/EntryPoint called targetPlatform which takes one of the following enumeration values:
  • IOSPlatform
  • AndroidPlatform
  • WindowsMobilePlatform
  • MobileWebPlatform
  • DesktopWebPlatform

Authors who prefer to specify a specific application or OS version can continue to use actionApplication as they do today.

/cc @shankarnat Is there a better term for Windows Mobile?